There is an electric power converter provided with semiconductor modules and a capacitor. Since the capacitor has ESR (equivalent series resistance), the capacitor generates heat by ripple current flowing therein. Further, although downsizing of the capacitor is requested along with downsizing of the electric power converter being demanded, ESR value tends to increase when the size of the capacitor is downsized such that the capacitor more easily generates heat.
Moreover, each of the semiconductor modules has a built-in switching element, and heat is generated by the flowing controlled current through the switching element. Such a heat is transmitted to the capacitor through bus bars, thus the temperature of the capacitor may rise.
Therefore, in order to cool the capacitor, a capacitor disposed on a heat sink is disclosed in the Japanese Patent Application Laid-Open Publication No. 2002-83915. The capacitor disclosed in the Publication No. 2002-83915 is fixed in a position such that a bottom surface thereof is in contact with the heat sink. Thereby, the capacitor is cooled from the bottom surface thereof.
However, directions or postures of a pair of end-face-electrodes (so-called metallikon surfaces) provided on both end faces of an element body of the capacitor relative to the heat sink are not described at all in the Publication No. 2002-83915. From a viewpoint of improving cooling performance of a capacitor, simply mounting the capacitor on the heat sink as disclosed in the Publication No. 2002-83915 is not sufficient, and there is room for improvement.